1. Field of the Invention
This invention relates to a process and apparatus for collecting shed blood from body cavities during surgical procedures and the like, and more particularly this invention relates a process and an apparatus for collecting shed blood for autotransfusion.
2. Brief Description of the Prior Art
Self-contained, disposable systems for the collection, anti-coagulation, filtration and reinfusion of blood shed into body cavities are known. Autotransfusion permits a patient's own shed blood to be recycled during the course of an operation. Autotransfusion is especially useful when appropriate banked blood is unavailable or when the patient's religious convictions, technical complications, or other factors dictate than banked blood not be used.
Prior art autotransfusion processes and apparatus often require that blood collected at a surgical site be stored in a first blood reservoir nad subsequently transferred to a second blood reservoir or blood bag, and also often require complicated priming and blood transfer procedures. These complicated procedures require expensive apparatus and increase the risk of error causing harm to the patient.
Other types of drainage units or devices for collecting fluids from body cavities are also known in the art. Initially, such devices comprised a plurality of bottles connected by hoses. One such bottle would form the collection chamber for matter being drawn from a body cavity and another bottle would form a water seal through which gases from the collection chamber would be bubbled and to which a source of suction would be connected. A third bottle could be employed as a manometer for monitoring and controlling the amount of vacuum, or negative pressure of the system, to a given pressure corresponding to a predetermined height of a column of water. These systems have gradually developed into disposable, single unit systems in which a plurality of internally connected chambers functioned as collection chambers, water seals and manometers.
In addition, it is known to employ such unitary drainage devices as sources of suction of collection of blood into specially adapted blood bags which are externally supported against collapse during blood collection. An example of an externally supported blood bag for collecting shed blood by suction is provided in U.S. Pat. No. 4,443,220 which discloses a collapsible sterilizable collection bag in combination with a special stent adapted to hold the bag in distended form as blood is collected in the presence of a vacuum in the bag. However, this system suffers from a major deficiency in that the vacuum in the interior of the bag must be released after blood collection in order to dislodge the bag from the stent. This release of vacuum could conceivably introduce ambient air into the interior of the bag. The ambient air may contain dangerous microorganisms which may contaminate the collected blood and render it unfit for transfusion back into the patient's body.
There is a clear need for an autotransfusion process and device which takes advantage of the simplicity and economy of unitary drainage devices as sources of suction for blood collection vessels which are releasably supported against pressure differential-induced collapse during blood collection, but which employ support means which are readily disengageable without requiring prior venting of the interior of the blood collection vessel to the atmosphere.
In other types of disposable devices for collecting body fluids, such as disclosed in U.S. Pat. Nos, 3,680,560, 3,685,517, and 3,866,608, a rigid cannister envelops an inner receiver formed from a rigid cap for the cannister sealed to a flexible liner for the cannister. Provision is made to actively exert a suction on the volume between the liner and the cannister to prevent the liner from collapsing when suction is applied within the liner to draw fluid into the liner. Providing means to create the countervailing suction increases the complexity and cost of manufacture of the device. Further, unless a separate port and suction line are provided for the countervailing suction, releasing suction to disassemble the device requires admitting air into the liner, thus increasing the risk of contamination of blood collected therein. On the other hand, using a separate port and suction line to provide a countervailing suction increases the complexity and cost of the apparatus, and further increases the complexity of operation of the device. There is a need for an apparatus and process which simplify the blood collection process, decreasing the complexity of the procedures required to collect blood for optional blood reuse and reducing the likelihood of operator error associated with prior art collection devices and procedures.